"Terminator Salvation" unfolds in a world of rubble and asphalt and steel and dirt and blood. Actually, unfolds is too weak a verb. The film explodes, coming at you like shrapnel. It is an unbroken series of action sequences that aim to make you duck and cower in your seat. It's a brutal portrait of a barbaric world where a human resistance movement and homicidal robots battle for survival.

Compared with James Cameron's thought-provoking action classics "Terminator" and "T2," this is a powerfully dumb movie. The earlier films told sprawling stories that interwove disparate threads to create a coherent whole. This one strains our credibility with its epic unlikelihoods, and tries to camouflage them with nonstop paroxysms. But it is undeniably exciting on a visceral level, and for many that will be enough.

The film is set in 2018 in nuke-blighted California, a lifeless moonscape full of two-lane highways and derelict buildings. It's an environment ideal for relentless pursuit and anxious hide-and-seek. And that is pretty much the daily grind for John Connor (Christian Bale) and his beleaguered band of brothers (plus a few nubile sisters).

They carry out risky assaults against SKYNET, the self-aware military computer network committed to eradicating humanity. The rebels score a few successes in these battles, but at awful cost. The odds of a human defeating a Terminator are about the same as a frog overpowering a lawn mower. The population of survivors dwindles with every turbulent scene.

The film proceeds with video-game logic. The humans have a chance to strike at the heart of SKYNET by jamming the communications link to its army of high-tech killers. But that goal can be interrupted at any moment by an onslaught of unmanned fighter jets, motorcycles or even mechanical eels patrolling the rivers.

There are color-by-number characters here. Connor is a stoic hero and mankind's link with the future: He shares many dewey-eyed looks with his fulsomely pregnant wife (Bryce Dallas Howard). Kyle Reese (Anton Yelchin) is the foolhardy teenager who matures in battle. Marcus Wright (Sam Worthington) fights alongside both, a tough convict with a mysterious background and motives. They spout hackneyed action movie dialogue, occasionally recycling trademark lines from earlier "Terminator" films. But in this kind of film, action speaks louder, and in "Terminator Salvation" it practically shouts itself hoarse.

Director McG ("Charlie's Angels") doesn't seem fully comfortable with the hypermasculine, humorless tone of the story. His showcase scenes betray the strain of creating them -- there's a sheen of flop sweat over the whole enterprise. In one memorable continuous shot, we stay right beside Connor as he battles Terminators, jumps into a helicopter, lifts off, loses control, crashes upside down, stumbles from the wreckage and fights some more. It's an impressive technical achievement, but it's such a showy piece of work that it pulls you out of the drama.

The Terminator franchise was built on thrills, imagination, narrative, emotion, believability, character development and watchability. "Terminator Salvation" has plenty of thrills.

Colin Covert • 612-673-7186